Piston



W. A. ROTH fug. 20, 1946.

Filedoct, 9, 1944 A'III Patenfed Aug. 2o, 194e PISTON William A. Roth, St. Paul, Minn.

Application October 9, 1944, Serial No. 557,813

Claims.

This is an improvement on and supplement to my construction as shown in my application for patent, Serial No. 489,692, ledpJune 4, 1943.

My invention relates to an improvement 'in pistons for internal combustion engines oi the four cycle type. A primary object of my invention is to remove, during the exhaust stroke, practically the entire exhaust gases that are ordinarily trapped in the clearance space of the present type of internal combustion engines.

Another object of primary importance is to provide a means for increasing the amount of fuel and air mixture drawn into the cylinders during the intake stroke, without the use of supercharger means when this is found to be desirable.

The foregoing objects provide a piston for internal combustion engines to increase eiiiciency, power,.and a great saving in fuel during the operation of the internal combustion engine. The increased efficiency and power obtained by using my piston in internal combustion engines tends to provide an engine of smaller weight for the same power than an internal combustion engine using the ordinary type of piston.

A further feature resides in providing Aan internal combustion enginewith lower'intake and compression temperatures, thereby permitting the use of lower octane fuel for the same compression ratio, or higher compression ratio for the same octane rating.

My piston is applicable to airplane motors, wherein I believe it will develop greater efficiency with a decrease in engine weight for the power developed by the engine using my pistons. These pistons may be used to advantage in automobile, Diesel, and other engines of the four cycle type,

where performance as dened herein is desirable.'

The details and further features of my pistons will be more fully hereinafter set forth.

In the drawing forming a part of my specification:

Figure 1 is a side elevation of my piston.

Figure 2 illustrates a diagrammatic cross-section of my piston.

Figure 3 is a section on the line 3-3 of Figure 2.

Figure 4 is a section on the line 4--4 of Figure 2.

Figure 5 is a section on the line 5-5 of Figure 2.

My piston A may be used in any type of four cycle internal combustion engine, and is provided with a head portion I0 which may be formed integral with the skirt 23 as illustrated in Figures 1 and 2.

The head III is formed with an internal depending cylindrical sleeve I2 which extends into the piston in parallel relation to the wall of the (Cl. 12S-78) 2 skirt 23; A depending cylindrical sleeve I'I with a taper cross-section extends internally into the piston, its center line being in parallel relation to the wall of the skirt 23, and situated between the sleeve I2 and the skirt 23 to provide the recesses I3 between the skirt 23 and the sleeve I'I, and the sleeve I1 and the sleeve I2.

On the lower end of the skirt 23, I provide a ring I4 which is threaded inside the lower end of the skirt 23 and is adapted to be fixed by the pins I5 to the skirt 23 of the piston. The inner end of the sleeve I4 is in the form of a cylindrical wall I6 which is parallel to the wall 23 of the skirt of the piston. A cylindrical sleeve I8 is formed with a taper cross-section whose center line'is parallel to the wall 23 of the skirt of thekpiston and thereby providing the annular recesses 8 which are complemental in size and shape to the recesses I3 on the inside of the upper end of the head of the piston A.

The cylindrical sleeve I2 and the cylindrical wall I6 have the same axis and extend in the same cylindrical plane, being spaced apart and adapted to provide a bearing for the ends of the wrist-pin sleeve B.

The wrist-pin 24 is mounted centrally between the ends in the sleeve B in any suitable manner and is adapted to support the upper end of the connecting rod C.

The sleeve B is constructed in cylindrical form with an outer diameter of such dimensions as to make a close fit within the apron 23, and an inner diameter at each end of the sleeve Bfto make a close t against the sleeves I2 and I6. 'I'he sleeve B is formed with outer and inner walls Il which are spaced apart to form the annular space I9. These walls I I extend on either side, that is, above and below, the wrist-pin to form the annular space I9 above the wrist-pin vand a similar annularspace 20 below the wrist-pin. The annular spaces I9 and 20 extend from the points 28 and 29, respectively, to each end of the sleeveB. The central portion 22 between the points 28 andA 29 maybe of solid construction with holes 2I, of such size as to permit cil or a uid to flow freely through them.

The inner and outer walls II have a uniform lthickness, while the ltapered walls I I and I8 are thicker at the base and tapered to a thin edge 9 at the outer end. In operation, when the ends of the Walls I I come into near contact with the bottoms of the recesses 8 or I3, the bases of the walls I'I or I8 will practically close the openings at the ends of the'sleeve B forming the annular spaces I9 or 20, thus preventing, or slowing to'a minimum, the iiow of oil or fluid from the bottom of the recesses 8 or I3 into the annular spaces I9,

My piston A will reciprocate in a cylinder (not shown) in the operation vof the internal combustion engine and the movement of the piston A will be beyond the movement of the sleeve B during :the suction and exhaust strokes of a four-cycle y engine.

During. the exhaust stroke the piston A, due to inertia force will move to a greater distance than the wrist-pin sleeve B, and during the suction stroke, the piston A will again move a greater recesses 8 and I3, the annular spaces I9 and 2li,

and the holes 2l filled with a fluid, such as oil or other suitable fluid, and kept under pressure, toV insure'that the said spaces will be kept filled at all times while the engine is inA operation, to make up any leakage, and to renew the fluid contlnuously to prevent its overheating due to violent agitation andy the heat of combustion.

This'iiuid may be passed through the connecting rodand wrist-pin as shown by the passageways 34 and 35, respectively, Y as in other well known manners.

Y The operation of my piston may be further set forth to more clearly define the operation as follows: Y

A1; the end of the power stroke which then becomes the beginning of the exhaust stroke, the upper faces 25 of the annular walls II of the wrist-pin section B- are in contact with the bottom 33- of the annularrecesses I3 of the piston A. The lower annular walls II of the wrist-pin section B will be withdrawn from the annular spaces 8a The piston A will stay in this position with respect to the sleeveB until a point, somewhat more than one-half the length of the motion of the sleeve B isl reached, when the sleeve B will begin to slow down, the piston A, being at its highest rate of speed at this point due to its inertia, will tend to continue at this` highest rate of speed and thus proceed towardsthe head of the cylinder at a faster rate than the sleeve B.

Simultaneously, while this action of the piston A is taking place, the oil or other uid in the annular spaces 8 is forced out, passing through the opening between the annular walls II and the annular wall of sloping cross-section I8, through the holes 2I of the sleeve B and into the annulary spaces I9 and thence into the spaces I3, as the walls I I are withdrawn from the spaces I3. i

Because of the sloping cross-section of the wall I8, the opening between the wall I8 and the walls I I will become smaller as the piston A moves forward, thus permitting the oil in the spaces 8 to ii'ow less freely. A pressure begins to build up, acting on the faces 32 of the lower walls II of the piston A tending to slow up the relative speed of the piston.

As the piston A rproceeds forward with respect to the sleeve B, the opening between the wall I8` and the walls I I becomes smaller and smaller, and as the piston A nears the end of its travel with respect tothe sleeve B, the opening between the wall' I8 and the walls II becomes so small that the flow through the opening is greatly restricted, and as the piston A reaches the end of'its travel, the'flow is entirely stopped as the faces 26 come 4. in contact with the faces 3.2 and so metal to metal contact is made without shock.

This action of the piston A permits it to travel Y to the top of the cylinder, thus forcing out practically all of the exhaust gases.

As the exhaust stroke is completed, andthe suction stroke begins, the piston A will remain in the position, with respect to the sleeve B, that it had at the end of the exhaust stroke, and will remain in this position up to a'point somewhat less than onehalf they length of' the suction stroke, when the sleeve B will again begin to slow down while the piston A -will tend to move vat its highestY rate of speed duringthis stroke and begin to move with respect to thegsleeve B, towards the crank end to its limit of travel and again make 'metal to metal contact without shock in ance gas is absent, the new charge will have an lower temperature.

Y At the beginning of the compression stroke, the

faces 25 will be in contact with the faces 30 at the bottom Vof the recesses I3, and will tend to remain in this position up to a pointv somewhat more than half the length of the compression stroke when the piston AV again will tend to move, due to its inertia, ahead of the sleeve B, but since the total pressure on the head of the piston A, due to thev compression of the charge is greater than the inertia force'of the piston A, the. pistonA will' remain in the positiorn with respect. to. the sleeve B, that it had at the beginning of they compression stroke. I

In this position at the beginning of the'power stroke, no shock` results at the end of the suction and the beginning of the power strokes. The piston A will remain in this position during the power stroke to the beginning of the exhaust stroke when the cycle will be repeated as described, no shock resulting at the end' ofthe pow--y er stroke, and thus; no shockl results throughout the cycle. Y

Construction of my piston is simple and I pro-Y 'I'he circulation of oil may be carried out in any manner to introduce a slight pressure in the cavities between the floating piston and the sleeve for supporting the same, which will lubricate the moving parts, as well as assisting to cool the same in the operation of the piston. A suiiicient oil release from these moving parts maybe carried on from the seeping of oil which will flow back to the crank case. It is also obvious that ant7 suitable means for lubrication by oil to the moving parts may be employed which may be made in accordance with the particular engine in which the piston is used, which means is not shown in the drawing, but which is well, known inv the art of internal combustion engines. Such` means is set forth in Steam Power and Internal Combustion Engines, by Craig and Anderson, pub-1 lished in 1937 by McGraw-Hill Book Co., Inc.,V and as outlined on pages 513 and 514. Y

type used heretofore.

I claim:

1. A piston for internal combustion engines, comprising a cylindrical sleeve carried by the Wrist-pin and the connecting rod, a. piston surrounding said sleeve and iloatingly supported thereon, a depending skirt having a tapered formation providing a thin outer edge and an enlarged base portion formed integral with the head of the piston and adapted to extend into a cylindrical annular passageway formed in said sleeve, a ring member anchored in the skirt of said piston and having a similarly formed tapered skirt adapted to extend into the opposite end of the annular passageway formed in the sleeve carried by the wrist-pin, whereby a tapered skirt extends into either end of said sleeve supported by the wrist-pin which is adapted to act as tapered plunger means Within the annular cylindrical passageways formed in said sleeve to gradually cushion the operation of said piston and sleeve when reciprocating in operation, when oil is introduced into said annular cylindrical passageway formed in the ends of said sleeve which floatingly supports said piston.

2. A piston for internal combustion engines, including a wrist-pin sleeve adapted to'be floatingly reciprocated in said piston by the operation of a connecting rod attached to said sleeve, an annular oil chamber formed in either end of said sleeve, a pair of tapered plunger walls having a sharp annular outer edge carried by said piston adapted to enter the said oil chamber and gradually cushion the operation of the piston by hydraulic means in the reciprocation of the same in its floating support on said sleeve.

3. A piston for internal combustion engines, including a piston body having a head and skirt means, a sleeve internally mounted in said piston body adapted to floatingly support said piston and having an annular oilchamber in each end, a wrist pin and connecting rod attached to said sleeve, and a pair of tapered sharp edged skirt walls adapted to extend from said piston into either end of said sleeve to operate in said oil chamber during the reciprocation thereof, whereslidably mounted within saidy piston body to which` the said wrist-pin is connected, the body of said piston being adapted to travel beyond the reciprocating movement of the piston supporting sleeve within the same, and cylindrical dashpot means extending to the wrist pin formed in each end of said sleeve, and plunger means on said pistonv adapted to extend into said dash-pot means in said sleeve, the area of said plunger means increasing at the base and diminishing at the outer end to a sharp edge, said dash-pot means with said plunger means forming a hydraulic cushion when a liquid is introduced into said dash-pot means of said sleeve, and about the area of said plunger means to cushion the end strokes of said piston in its reciprocating movement.

5. A piston for cylinders, having a body portion, a series of ring grooves formed in said body portion, long tapered plungers projecting within said piston body from either end, a cylindrical 'dash-pot sleeve reciprocable Within the piston body, a wrist-pin connecting said dash-pot sleeve with a connecting rod, said tapered plungers being adapted to extend into the dash-pot of said sleeve, whereby when liquid is introduced into said dashpot sleeve and around said plungers, the reciprocating movement of said piston will be cushioned at the ends of its stroke, by the retarding action of said dash-pot sleeve and plungers when a fluid is introduced into said dash-pot, and said piston is permitted to travel beyond the reciprocating movement of said dash-pot sleeve.

WILLIAM A. ROTH. 

